Light collimating and diffusing film and system for making the film

ABSTRACT

A light collimating and diffusing film and a method for making the film are provided. The film includes a plastic layer having a first side and a second side opposite the first side and at least a first peripheral edge. The first side has a first textured surface, wherein between 7 to 20 percent of slope angles on the first textured surface proximate a first axis has a value between zero and five degrees. The first axis is substantially parallel to the first peripheral edge. The plastic layer collimates light propagating therethrough.

CROSS REFERENCE TO RELATED APPLICATION

The application is a divisional application of U.S. application, Ser.No. 11/429,842, filed May 8, 2006, the contents of which areincorporated herein by reference thereto. U.S. application Ser. No.11/429,842 is a divisional application of U.S. Ser. No. 10/710,585,filed on Jul. 22, 2004 which is now U.S. Pat. No. 7,092,163, issued onAug. 15, 2006, the contents of which are incorporated herein byreference thereto.

BACKGROUND OF THE INVENTION

A light diffusive film has been developed for receiving light anddiffusing the light. The light diffusive film is manufactured usingmultiple manufacturing steps. First, a plurality of polystyrene beadsare disposed in an acrylate solution. The acrylate solution is thenapplied to a surface of a plastic film. Thereafter, the plastic film isheated to cure the acrylate and to bond the polystyrene beads to theplastic film. A significant drawback with the manufacturing process ofthe light diffusive film is that it requires several relatively complexsteps to coat the film with the acrylate solution and polystyrene beads.Further, the manufacturing process is relatively expensive to perform.

Accordingly, there is a need for a light diffusive film that can bemanufactured using a simplified process without utilizing polystyrenebeads or an acrylate solution.

BRIEF DESCRIPTION OF THE INVENTION

A light collimating and diffusing film in accordance with an exemplaryembodiment is provided. The film includes a plastic layer having a firstside and a second side opposite the first side and at least a firstperipheral edge. The first side has a textured surface, wherein between7 to 20 percent of slope angles on the first textured surface proximatea first axis has a value between zero and five degrees. The first axisis substantially parallel to the first peripheral edge. The plasticlayer collimates light propagating therethrough.

A method for manufacturing a light collimating and diffusing film inaccordance with another exemplary embodiment is provided. The methodincludes extruding heated plastic through a die to form a plastic layer.The plastic layer has a first side and a second side opposite the firstside and at least a first peripheral edge. The plastic layer extendsalong both a first axis and a second axis. The first axis issubstantially parallel to the first peripheral edge. The second axis issubstantially perpendicular to the first axis. The method furtherincludes cooling at least one of first and second rotating cylindricalrollers below a predetermined temperature. The method further includesmoving the plastic layer between first and second rotating cylindricalrollers. The first cylindrical roller contacts the first side of theplastic layer and the second cylindrical roller contacts the secondside. The first cylindrical roller forms a first textured surface on thefirst side of the plastic layer, wherein between 7 to 20 percent ofslope angles on the first textured surface proximate the first axis havea value between zero and five degrees.

A system for manufacturing a light collimating and diffusing film inaccordance with another exemplary embodiment is provided. The systemincludes an extruder device operably coupled to a die. The extruderdevice urges heated plastic through the die to form a plastic layer. Theplastic layer has a first side and a second side opposite the first sideand at least a first peripheral edge. The plastic layer extends alongboth a first axis and a second axis. The first axis is substantiallyparallel to the first peripheral edge. The second axis is substantiallyperpendicular to the first axis. The system further includes first andsecond cylindrical rollers disposed proximate one another for receivingthe plastic layer. The system further includes a cooling deviceconfigured to cool at least one of the first and second cylindricalrollers below a predetermined temperature. The first cylindrical rollercontacts the first side of the plastic layer and forms a first texturedsurface on the first side of the plastic layer. The second cylindricalroller contacts the second side of the plastic layer, wherein between 7to 20 percent of slope angles on the first textured surface proximatethe first axis have a value between zero and five degrees.

A method for manufacturing a light collimating and diffusing film inaccordance with another exemplary embodiment is provided. The methodincludes heating a plastic layer having a first side and a second side.The plastic layer has a first side and a second side opposite the firstside and at least a first peripheral edge. The plastic layer extendsalong both a first axis and a second axis. The first axis issubstantially parallel to the first peripheral edge. The second axis issubstantially perpendicular to the first axis. The method furtherincludes heating at least one of the first and second cylindricalrollers above a predetermined temperature. The method further includesmoving the plastic layer between first and second rotating cylindricalrollers wherein the first cylindrical roller contacts the first side ofthe plastic layer and the second cylindrical roller contacts the secondside. The first cylindrical roller forms a first textured surface on thefirst side proximate the first axis of the plastic layer, whereinbetween 7 and 20 percent of slope angles on the first textured surfaceproximate the first axis have a value between zero and five degrees.

A system for manufacturing a light collimating and diffusing film inaccordance with another exemplary embodiment is provided. The systemincludes a first heating device configured to heat a plastic layer. Theplastic layer has a first side and a second side opposite the first sideand at least a first peripheral edge. The plastic layer extends alongboth a first axis and a second axis. The first axis is substantiallyparallel to the first peripheral edge. The second axis is substantiallyperpendicular to the first axis. The system further includes first andsecond cylindrical rollers being disposed proximate one another forreceiving the plastic layer. The system further includes a secondheating device configured to heat at least one of first and secondcylindrical rollers. The first cylindrical roller contacts the firstside of the plastic layer and forms a first textured surface on thefirst side and the second cylindrical roller contacts the second side ofthe plastic layer, wherein between 7 to 20 percent of slope angles onthe first textured surface proximate the first axis have a value betweenzero and five degrees.

A tool for forming a textured surface on a light collimating anddiffusing film in accordance with another exemplary embodiment isprovided. The tool includes a cylindrical portion disposed about a firstaxis and having an external textured surface and first and second ends.The cylindrical portion further includes a first line disposed proximatethe external textured surface extending substantially across thecylindrical portion substantially perpendicular to the first end. Thecylindrical portion further includes a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end. The external textured surface has aplurality of projecting portions and a plurality of trough portions,wherein each projecting portion extends outwardly from at least oneadjacent trough portion. The plurality of projecting portions and theplurality of trough portions define a plurality of slope angles, whereinbetween 7 to 20 percent of the slope angles on the external texturedsurface proximate the first line or the second line have a value betweenzero and five degrees.

A method for forming a textured surface on a cylindrical roller inaccordance with another exemplary embodiment is provided. Thecylindrical roller is disposed about a first axis and has an externaltextured surface and first and second ends. The cylindrical rollerfurther includes a first line disposed proximate the external texturedsurface extending substantially across the cylindrical rollersubstantially perpendicular to the first end. The cylindrical rollerfurther includes a second line extending around a periphery of thecylindrical portion substantially a predetermined distance from thefirst end. The method includes rotating the cylindrical roller at apredetermined rotational speed about the first axis. The method furtherincludes emitting a pulsating energy beam that contacts the othersurface of the cylindrical roller at a predetermined intensity andmoving the energy beam from the first end to the second end of thecylindrical roller during the rotation of the cylindrical roller. Theenergy beam removes portions of the outer surface to obtain the texturedsurface, wherein between 7 to 20 percent of slope angles on the texturedsurface proximate the first line or the second line have a value betweenzero and five degrees.

A method for forming a textured surface on a cylindrical roller inaccordance with another exemplary embodiment is provided. Thecylindrical roller is disposed about a first axis and has an externaltextured surface and first and second ends. The cylindrical rollerfurther includes a first line disposed proximate the external texturedsurface. The first line extends substantially across the cylindricalroller substantially perpendicular to the first end. The cylindricalroller further includes a second line extending around a periphery ofthe cylindrical portion substantially a predetermined distance from thefirst end. The method includes rotating the cylindrical roller at apredetermined rotational speed about the first axis in an electrolytefluid. The cylindrical roller is electrically grounded. The methodfurther includes applying a predetermined current density to theelectrolyte fluid wherein metal ions in the fluid bond to the outersurface of the cylindrical roller to form the textured surface, whereinbetween 7 to 20 percent of slope angles on the textured surfaceproximate the first line or the second line have a value between zeroand five degrees.

A method for forming a textured surface on a cylindrical roller inaccordance with another exemplary embodiment is provided. Thecylindrical roller is disposed about a first axis and has an externaltextured surface and first and second ends. The cylindrical rollerfurther includes a first line disposed proximate the external texturedsurface. The first line extends substantially across the cylindricalroller substantially perpendicular to the first end. The cylindricalroller further includes a second line extending around a periphery ofthe cylindrical portion substantially a predetermined distance from thefirst end. The method further includes rotating the cylindrical rollerat a predetermined rotational speed about the first axis in a fluidcontaining metal ions and non-metal particles. The method furtherincludes chemically bonding the metal ions and the non-metal particlesto the outer surface of the cylindrical roller to form the texturedsurface, wherein between 7 and 20 percent of slope angles on thetextured surface proximate the first line or the second line have avalue between zero and five degrees.

A method for forming a textured surface on a cylindrical roller inaccordance with another exemplary embodiment is provided. Thecylindrical roller is disposed about a first axis and having an externaltextured surface and first and second ends. The cylindrical rollerfurther includes a first line disposed proximate the external texturedsurface. The first line extends substantially across the cylindricalroller substantially perpendicular to the first end. The cylindricalroller further includes a second line extending around a periphery ofthe cylindrical portion substantially a predetermined distance from thefirst end. The method includes rotating the cylindrical roller at apredetermined rotational speed about the first axis. The method furtherincludes applying a dielectric fluid on the cylindrical roller. Themethod further includes iteratively discharging an electric spark fromone or more electrodes disposed proximate the cylindrical roller. Theelectric spark contacts the outer surface of the cylindrical roller thatheats and melts a predetermined amount of metal on the cylindricalroller to form the textured surface. The electric spark is moved fromthe first end to the second end of the cylindrical roller during therotation of the cylindrical roller, wherein between 7 and 20 percent ofslope angles on the textured surface proximate the first line or thesecond line have a value between zero and five degrees.

A method for forming a textured surface on a cylindrical roller inaccordance with another exemplary embodiment is provided. Thecylindrical roller is disposed about a first axis and has an externaltextured surface and first and second ends. The cylindrical rollerfurther includes a first line disposed proximate the external texturedsurface. The first line extends substantially across the cylindricalroller substantially perpendicular to the first end. The cylindricalroller further includes a second line extending around a periphery ofthe cylindrical portion substantially a predetermined distance from thefirst end. The method includes rotating the cylindrical roller at apredetermined rotational speed about the first axis. The method furtherincludes iteratively contacting the outer surface of the cylindricalroller using a cutting tool at a predetermined frequency. The cuttingtool moves from the first end to the second end of the cylindricalroller during the rotation of the cylindrical roller. The cutting toolremoves portions of the outer surface to obtain the textured surface,wherein between 7 and 20 percent of slope angles on the textured surfaceproximate the first line or the second line have a value between zeroand five degrees.

A method for forming a textured surface on a cylindrical roller inaccordance with another exemplary embodiment is provided. Thecylindrical roller is disposed about a first axis and has an externaltextured surface and first and second ends. The cylindrical rollerfurther includes a first line disposed proximate the external texturedsurface. The first line extends substantially across the cylindricalroller substantially perpendicular to the first end. The cylindricalroller further includes a second line extending around a periphery ofthe cylindrical portion substantially a predetermined distance from thefirst end. The method includes coating the cylindrical roller with achemically resistant layer, wherein the chemically resistant layer isremoved at predetermined locations to expose the underlying cylindricalroller surface at the predetermined locations. The method furtherincludes rotating the cylindrical roller at a predetermined rotationalspeed about the first axis in a container containing an etchingsolution. The etching solution removes portions of the cylindricalroller at the predetermined locations to obtain the textured surface,wherein between 7 and 20 percent of slope angles on the textured surfaceproximate the first line or the second line have a value between zeroand five degrees.

A back lighted device in accordance with another exemplary embodiment isprovided. The back lighted device includes a light source. The backlighted device further includes a light guide disposed proximate thelight source for receiving light from the light source. The back lighteddevice further includes at least one plastic layer having a first sideand a second side opposite the first side and at least a firstperipheral edge. The first side has a first textured surface, whereinbetween 7 and 20 percent of slope angles on the first textured surfaceproximate a first axis have a value between zero and five degrees, thefirst axis being substantially parallel to the first peripheral edge,wherein the plastic layer collimates light propagating therethrough.

A light collimating and diffusing film in accordance with anotherexemplary embodiment is provided. The film includes a unitary layerwherein greater than or equal to 80 percent of a total mass of theunitary layer comprises a polycarbonate compound. The unitary layer hasa first side and a second side opposite the first side and at least afirst peripheral edge. The first side has a first textured surface,wherein between 7 and 20 percent of slope angles on the first texturedsurface proximate a first axis have a value between zero and fivedegrees. The first axis is substantially parallel to the firstperipheral edge. The plastic layer collimates light propagatingtherethrough.

Other systems and/or methods according to the embodiments will become orare apparent to one with skill in the art upon review of the followingdrawings and detailed description. It is intended that all suchadditional systems and methods be within the scope of the presentinvention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a back lighted device in accordance withan exemplary embodiment;

FIG. 2 is a schematic of a portion of the back lighted device of FIG. 1;

FIG. 3 is a cross-sectional schematic of a light collimating anddiffusing film utilized in the back lighted device of FIG. 1 inaccordance with another exemplary embodiment;

FIG. 4 is a graph indicating a slope distribution on a front surface ofthe light collimating and diffusing film;

FIG. 5 is a top view of a cylindrical roller illustrating exemplarytrajectories for determining a slope angle distribution;

FIG. 6 is a top view of a light collimating and diffusing filmillustrating exemplary trajectories for determining a slope angledistribution;

FIG. 7 is a top view of a cylindrical roller illustrating exemplarytrajectories for determining a slope angle distribution;

FIG. 8 is a top view of a light collimating and diffusing filmillustrating exemplary trajectories for determining a slope angledistribution;

FIG. 9 is a schematic of a melt calendaring system for manufacturing alight collimating and diffusing film in accordance with anotherexemplary embodiment;

FIG. 10 is a schematic of an embossing system for manufacturing a lightcollimating and diffusing film in accordance with another exemplaryembodiment;

FIG. 11 is a schematic of an energy beam engraving system for obtaininga textured surface on a cylindrical roller in accordance with anotherexemplary embodiment;

FIG. 12 is a schematic of a textured surface on a cylindrical rollerobtained using the energy beam engraving system of FIG. 11;

FIG. 13 is a schematic of a textured surface on a light collimating anddiffusing film obtained using the cylindrical roller of FIG. 12;

FIG. 14 is a schematic of a particle and metal ion co-deposition systemfor obtaining a textured surface on a cylindrical roller in accordancewith another exemplary embodiment;

FIG. 15 is a schematic of a textured surface on a cylindrical rollerobtained using the particle and metal ion co-deposition system of FIG.14;

FIG. 16 is a schematic of a textured surface on a light collimating anddiffusing film obtained using the cylindrical roller of FIG. 15;

FIG. 17 is a schematic of a metal ion deposition system for obtaining atextured surface on a cylindrical roller in accordance with anotherexemplary embodiment;

FIG. 18 is a schematic of a micro-machining engraving system forobtaining a textured surface on a cylindrical roller in accordance withanother exemplary embodiment;

FIG. 19 is an enlarged front view of a cutting cool utilized in thesystem of FIG. 18;

FIG. 20 is an enlarged side view of the cutting cool utilized in thesystem of FIG. 18;

FIG. 21 is a schematic of chemical etching engraving system forobtaining a textured surface on a cylindrical roller in accordance withanother exemplary embodiment;

FIG. 22 is an enlarged cross-sectional view of a portion of thecylindrical roller utilized by the system of FIG. 21; and

FIG. 23 is a schematic of an electric discharge engraving system forobtaining a textured surface on a cylindrical roller in accordance withanother exemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, a back lighted device 20 for illuminating aliquid crystal display device (not shown) is illustrated. The backlighted device 20 includes a light source 22, a reflector film 24, alight guide 26, a light collimating and diffusing film 28, a lightcollimating film 30, a light collimating film 32, and a light diffuserfilm 34. As shown, the light source 22 is disposed at a first end of thelight guide 26. Further, the reflector film 24 is disposed, proximate afirst side of the light guide 26. A first side of the light collimatingand diffusing film 28 is disposed proximate a second side of the lightguide 26 and is spaced apart from the light guide 26 utilizing posts 36,38. The posts 36, 38 form an air gap 40 between the light guide 26 andthe film 28. The light collimating film 30 is disposed proximate asecond side of the film 28. Finally, the light collimating film 32 isdisposed proximate the light collimating film 30 and the light diffusingfilm 34 is disposed proximate the light collimating film 32.

The path of an exemplary light beam propagating through both the lightguide 26 and the light collimating and diffusing film 28 will now beexplained. The light source 22 emits a light beam 42 that propagatesthrough the light guide 26 and is refracted therein toward an axis 44that is substantially perpendicular to a top surface of the light guide26. When the light beam 42 exits the light guide 26 and the air gap 40,the light beam 42 is refracted away from the axis 44 at approximately 45degrees. When the light beam 42 enters the light collimating anddiffusing film 28, the film 28 refracts the light beam 42 toward theaxis 44. Thereafter, when the light beam 42 exits the film 28 to lightbeam is refracted away from the axis 44 at approximately 31 degrees.Thereafter, the light beam 42 enters the bottom side of the lightcollimating film 30 at a 31 degree angle relative of the axis 44 andpropagates through the film 30. The film 30 refracts the light beam at atop surface thereof to a zero degree angle relative to the axis 44.Because the light beam enters film 32 at a zero degree angle relative tothe axis 44, the film 32 provides a relatively high luminance along axis44.

Referring to FIGS. 2 and 3, the light collimating and diffusing film 28will now be explained in greater detail. The film 28 is utilized torefract light beams toward the axis 44. The film 28 is constructed froma unitary plastic layer having a thickness in a range of 0.025-10millimeters. Of course, the film 28 can be constructed with a thicknessless than 0.025 millimeters or greater than 10 millimeters. The film 28has an optical brightener compound disposed in the plastic layer whereina mass of the optical brightener compound is in a range of 0.001-1.0percent of a total mass of the plastic layer. The film 28 furtherincludes an antistatic compound, such as fluorinated phosphoniumsulfonate, disposed in the plastic layer. Fluorinated phosphoniumsulfonate has a general formula: {CF₃(CF₂)_(n)(SO₃)}⁹{P(R₁)(R₂)(R₃)(R₄)}^(Φ) wherein F is Fluorine; n is an integer of from1-12, S is sulfur; R₁, R₂ and R₃ are the same element, each having analiphatic hydrocarbon radical of 1-8 carbon atoms or an aromatichydrocarbon radical of 6-12 carbon atoms; and R₄ is a hydrocarbonradical of 1-18 carbon atoms. The film 28 further includes anultraviolet (UV) absorber compound disposed in the plastic layer whereina mass of the UV absorber compound is in a range of 0.01-1.0 percent ofa total mass of the plastic layer. The film 28 includes a textured topsurface 46 having a plurality of projecting portions 52 and a pluralityof trough portions 54. The average height of the plurality of projectingportions 52 is within a range of 25-75 percent of an average width ofthe plurality of projecting portions. Further, the average width of theplurality of projecting portions 52 is within a range of 0.5-100microns. The projecting portions 52 and the trough portions 54 aredistributed on the top surface 46 to obtain a desired slope angledistribution.

The slope angle distribution is a distribution of a plurality of slopeangles along at least one predetermined trajectory on the lightcollimating and diffusing film 28. Further, each slope angle (φ) iscalculated using the following equation:Slope Angle φ=arc tan|Δh/Δw| where:

(Δw) represents a predetermined width along the textured surface 46,such as 0.5 microns for example;

(Δh) represents a height difference between (i) a lowest position on thetextured surface 46 along the width (Δw), and (ii) a highest position onthe surface 46 along the width (Δw).

The slope angles reported in this patent application for a plastic filmcan be calculated from filtered two dimensional surface profile datagenerated using a Surfcoder ET 4000 instrument manufactured by KosakaLaboratory Limited, Tokyo, Japan. The operational settings of theSurfcoder ET 4000 instrument are as follows: Cutoff=0.25 mm. SampleLength and Evaluation Length both set at 10 mm. The speed being set at0.1 mm/second with profile data being obtained at 8000 equally spacedpoints.

The slope angles reported in this patent application for a cylindricalroller can be calculated from filtered two dimensional surface profiledata generated using a Surfcoder SE 1700α instrument also manufacturedby Kosaka Laboratory Limited. The operational settings of the SurfcoderSE 1700α instrument are as follows: Evaluation Length=7.2 mm, CutoffLc=0.800 mm. The speed being set at 0.500 mm/second with profile databeing obtained at 14400 points.

The slope angle distribution can be determined along a predeterminedreference trajectory or line on the plastic layer. Alternately, a slopeangle distribution can be determined on an entire surface of the plasticlayer using multiple reference trajectories or lines.

For example, referring to FIGS. 6 and 8, a plurality of slope angles (φ)can be calculated along a predetermined trajectory across texturedsurface 46, such as an axis 62 that is parallel to an edge 61 of thefilm 28, or an axis 60 that is perpendicular to the axis 62.Alternately, the plurality of slope angles (φ) can be calculated along aline 80 or a line 82. In one or more of the foregoing trajectories, thedesired slope angle distribution comprises between 7 and 20 percent ofslope angles having a value between zero and five degrees.

Referring to FIG. 4, a graph illustrating a slope angle distribution ona textured surface 46 on a first side of the film 28 in accordance withan exemplary embodiment is illustrated. The inventors herein haverecognized that when 20 percent or less of slope angles on the texturedsurface 46, and preferably between 7 and 20 percent of slope angles onthe surface 46, have a value between zero and five degrees, adjacentbrightness enhancing films (e.g., films 30 and 32) have increasedluminance with respect to the axis 44.

Referring to FIGS. 1 and 2, the percentage of slope angles between zeroand five degrees on the textured top surface 46 controls the angle ofthe light that exits the film 28 and enters the light collimating film30. When the percentage of slope angles on the surface 46 is about 16percent, the light exits the film 28 at a 31 degree angle relative toaxis 44 as shown. In an alternate embodiment, if it is desirable for thelight to exit the film 28 at an angle greater than 31 degrees relativeto the axis 44, then the film 28 could be constructed with greater than16 percent of the slope angles having a value between zero and fivedegrees. In another alternate embodiment, if it is desirable for thelight to exit the film 28 at an angle less than 31 degrees relative tothe axis 44, then the film 28 could be constructed with less than 16percent of the slope angles having a value between zero and fivedegrees.

Referring to FIG. 3, the film 28 also has a textured surface 48 on asecond side of the film 28. The textured surface 48 has a slope angledistribution wherein greater than or equal to or 70 percent of the slopeangles on the textured surface 48 have a value between zero and fivedegrees.

Referring to FIG. 9, a melt calendaring system 100 for manufacturing atextured plastic layer 106 that can be subsequently cut into apredetermined shape to form light collimating and diffusing film 28 isillustrated. The melt calendaring system 100 includes an extruder device102, a die 104, cylindrical rollers 64, 108, 110, 112, 114, 116, acylindrical spool 118, a roller cooling system 120, a film thicknessscanner 122, motors 124, 126, 128, and a control computer 130.

The extruder device 102 is provided to heat plastic above apredetermined temperature to induce the plastic to have a liquid state.The extruder device 102 is operably coupled to the die 104 and to thecontrol computer 130. In response to a control signal (E) from thecontrol computer 130, the extruder device 102 heats plastic thereinabove a predetermined temperature and urges the plastic through the die104 to form the plastic layer 106.

The cylindrical rollers 64, 108 are provided to receive the plasticlayer 106 therebetween from the die 104 and to form a textured surfaceon a least one side of the plastic layer 106. The cylindrical rollers64, 108 are preferably constructed from steel and are operably coupledto the roller cooling system 120. Of course, in an alternate embodiment,the cylindrical rollers 64, 108 may be constructed from other metallicor non-metallic materials known to those skilled in the art. The rollercooling system 120 maintains a temperature of the rollers 64, 108 belowpredetermined temperature to solidify the plastic layer 106 as it passesbetween the rollers 64, 108. The cylindrical roller 64 has a texturedsurface 107 wherein between 7 to 20 percent of slope angles on thetextured surface 107 or along at least one trajectory on the texturedsurface 107 have a value between zero and five degrees. Thus, when thecylindrical roller 64 contacts a first side of the plastic layer 106,the cylindrical roller 64 forms a textured surface on the plastic layer106, wherein between 7 and 20 percent of slope angles on the surface 46of the layer 106 or along at least one trajectory on the texturedsurface 46 have a value between zero and five degrees.

Referring to FIGS. 5 and 7, the slope angles (φ) of the cylindricalroller 64 can be determined along a predetermined trajectory across theouter surface 107, such as a line 68 extending substantially across theroller 64 substantially perpendicular to the end 211 or a line 70extending substantially around a periphery of the roller 64 apredetermined distance from the end 211. Alternately, the slope angles(φ) of the cylindrical roller 64 can be determined along a line 84 or aline 86.

The cylindrical rollers 110, 112 are configured to receive the plasticlayer 106 after the layer 106 has passed between the rollers 64, 108.The position of the cylindrical roller 110 can be adjusted to vary anamount of surface area of the plastic layer 106 that contacts thecylindrical roller 108. The cylindrical roller 110 is operably coupledto the roller cooling system 120 that maintains the temperature of theroller 110 below a predetermined temperature for solidifying the plasticlayer 106. The cylindrical roller 112 receives a portion of the plasticlayer 106 downstream of the roller 110 and directs the plastic layer 106toward the cylindrical rollers 114, 116.

The cylindrical rollers 114, 116 are provided to receive the plasticlayer 106 therebetween and to move the plastic layer 106 toward thecylindrical spool 118. The cylindrical rollers 114, 116 are operablycoupled to the motors 126, 124, respectively. The control computer 130generates control signals (M1), (M2) which induce motors 124, 126,respectively, to rotate the rollers 116, 114 in predetermined directionsfor urging the plastic layer 106 towards the spool 118.

The cylindrical spool 118 is provided to receive the textured plasticlayer 106 and to form a roll of plastic layer 106. The cylindrical spool118 is operably coupled to the motor 128. The control computer 130generates a control signal (M3) that induces the motor 128 to rotate thespool 118 in predetermined direction for forming a roll of the plasticlayer 106.

The film thickness scanner 122 is provided to measure a thickness of theplastic layer 106 prior to the layer 106 being received by thecylindrical rollers 114, 116. The film thickness scanner 122 generates asignal (T1) indicative of the thickness of the plastic layer 106 that istransmitted to the control computer 130.

Referring to FIG. 10, an embossing system 150 for manufacturing aplastic layer 154 that can be subsequently cut into a predeterminedshape to form the film 28 is illustrated. The embossing system 150includes a cylindrical spool 152, a film-heating device 156, cylindricalrollers 64, 160, 162, 164, 166, 168, a cylindrical spool 170, a rollerheating system 172, a film thickness scanner 174, motors 176, 178, 180,and a control computer 182.

The cylindrical spool 152 is provided to hold the plastic layer 150thereon. When the cylindrical spool 152 rotates, a portion of theplastic layer 150 is unwound from the spool 152 and moves toward thecylindrical rollers 64, 160.

The film-heating device 156 is provided to heat the plastic layer 150 asit moves from the cylindrical spool 152 towards the cylindrical rollers64, 160. The control computer 182 generates a signal (H1) that istransmitted to the film-heating device 156 that induces the device 156to heat the plastic layer 150 above a predetermined temperature.

The cylindrical rollers 64, 160 are provided to receive the plasticlayer 154 therebetween from the cylindrical spool 152 and to form atextured surface on a least one side of the plastic 154. The cylindricalrollers 64, 160 are preferably constructed from steel and are operablycoupled to the roller heating system 172. Of course, in an alternateembodiment, the cylindrical rollers 64, 160 may be constructed fromother metallic or non-metallic materials known to those skilled in theart. The roller heating system 172 maintains a temperature of therollers 64, 160 above a predetermined temperature to at least partiallymelt the plastic layer 154 as it passes between the rollers 64, 160. Thecylindrical roller 64 has an outer textured surface 107 wherein between7 and 20 percent of slope angles on the textured surface 107 have avalue between zero and five degrees. Thus, when the cylindrical roller64 contacts a first side of the plastic layer 154, the cylindricalroller 64 forms a textured surface on the plastic layer 154, whereinbetween 7 and 20 percent of slope angles on the top surface of the layer154 have a value between zero and five degrees.

The cylindrical rollers 162, 164 are configured to receive the plasticlayer 154 after the layer 154 has passed between the rollers 64, 160.The position of the cylindrical roller 162 can be adjusted to vary anamount of surface area of the plastic layer 154 that contacts thecylindrical roller 160. The cylindrical roller 164 receives a portion ofthe plastic layer 154 downstream of the roller 162 and directs theplastic layer 154 toward the cylindrical rollers 166, 168.

The cylindrical rollers 166, 168 are provided to receive the plasticlayer 154 and to move the plastic layer 154 toward the cylindrical spool170. The cylindrical rollers 166, 168 are operably coupled to the motors178, 176, respectively. The control computer 182 generates controlsignals (M4), (M5) which induce motors 176, 178, respectively, to rotatethe rollers 168, 166 in predetermined directions for urging the plasticlayer 154 towards the spool 170.

The cylindrical spool 170 is provided to receive the plastic layer 154and to form a roll of plastic layer 154. The cylindrical spool 170 isoperably coupled to the motor 180. The control computer 182 generates acontrol signal (M6) that induces the motor 180 to rotate the spool 170in predetermined direction for forming a roll of the plastic layer 154.

The film thickness scanner 174 is provided to measure a thickness of theplastic layer 154 prior to the layer 154 being received by thecylindrical rollers 114, 116. The film thickness scanner 174 generates asignal (T2) indicative of the thickness of the plastic layer 154 that istransmitted to the control computer 182.

Referring to FIG. 11, a system 200 for forming a textured surface on thecylindrical roller 64 in accordance with an exemplary embodiment isillustrated. The cylindrical roller 64 has a textured surface can beutilized in the melt calendaring system 100 or the embossing system 150to form a textured plastic layer used to obtain the film 28. The system200 includes a laser 202, a linear actuator 204, a motor 206, and acontrol computer 208.

The laser 202 is provided to emit a pulsating laser beam that contactsan outer surface at a predetermined intensity to remove portions of theouter surface 209 to obtain a textured surface thereon. The laser beamemitted by the laser 202 has a focal diameter at the outer surface 209of the cylindrical roller 64 in a range of 0.005-0.5 millimeters.Further, the laser beam has an energy level in a range of 0.05-1.0Joules delivered over a time period in a range of 0.1-100 microsecondsfor a predetermined area of the cylindrical roller 64. The laser 202 isoperably coupled to the control computer 208 and generates the laserbeam in response to a control signal (C1) being received from thecontrol computer 208. The laser 102 comprises a neodymium (Nd):yttrium,aluminum, garnet (YAG) laser configured to emit a laser beam having awavelength of 1.06 microns. It should be understood, however, that anylaser source capable of forming the desired textured surface on acylindrical roller can be utilized. In an alternate embodiment, thelaser 202 can be replaced with an electron beam emission deviceconfigured to form the desired textured surface on a cylindrical roller.In still another alternate embodiment, the laser 202 can be replacedwith an ion beam emission device configured to form the desired texturedsurface on a cylindrical roller.

The linear actuator 204 is operably coupled to the laser 202 for movingthe laser 202 along an axis 203. The axis 203 is substantially parallelto the outer surface 209 of the cylindrical roller 64. The linearactuator 204 moves the laser 202 relative to the cylindrical roller 64at a speed within a range of 0.001-0.1 millimeters per second0. In analternate embodiment, linear actuator 204 could be coupled tocylindrical roller 64 to move the roller 64 in an axial directionrelative to a stationary laser.

The motor 206 is operably coupled to the cylindrical roller 64 to rotatethe roller 64 while the linear actuator 204 is moving the laser 202along the axis 203 from an end 211 to an end 213 of the roller 64. Thecontrol computer 200 generates a signal (M7) that induces the motor 206to rotate the cylindrical roller 64 at a predetermined speed. Inparticular, the motor 206 rotates the cylindrical roller 64 such that alinear speed of the outer surface 209 is within a range of 25-2500millimeters per second.

Referring to FIG. 12, a cross-sectional view of a portion of a texturedsurface 209 of the cylindrical roller 64 is illustrated. The texturedsurface 209 was obtained utilizing the energy beam engraving system 200.The textured surface 209 has a slope angle distribution wherein between7 and 20 percent of slope angles on the textured surface 209 have avalue between zero and five degrees.

Referring to FIG. 13, a cross-sectional view of a portion of a texturedsurface 215 of the light collimating and diffusing film 28 cut from atextured plastic layer formed by the cylindrical roller 64 isillustrated. The film 28 has a slope angle distribution wherein between7 and 20 percent of slope angles on the film 28 have a value betweenzero and five degrees.

Referring to FIG. 14, a system 230 for forming a textured surface on thecylindrical roller 251 in accordance with another exemplary embodimentis illustrated. The cylindrical roller 251 can be utilized either in themelt calendaring system 100 or the embossing system 150 to form atextured plastic layer that can be subsequently cut into a predeterminedshape to obtain a film having the physical characteristics of film 28described above. The system 230 includes a housing 232, a motor 242, apump 244, a temperature control unit 246, a particle and metal ionreplenishment unit 248, and a control computer 250.

The housing 232 defines an interior region 234 for receiving acylindrical roller 251. The housing 232 holds a fluid containing aplurality of metal ions 236 and a plurality of non-metal particles 238.The non-metal particles have a size of diameter in a range of 1-100micrometers. The non-metal particles comprise silica particles. Thesilica particles can be solid silica particles, hollow silica particles,or porous silica particles. In an alternate embodiment, the non-metalparticles comprise alumina particles. The alumina particles can be solidalumina particles, hollow alumina particles, or porous aluminaparticles. In yet another alternate embodiment, the non-metal particlescomprise diamond particles. The metal ions comprise nickel ions andnickel alloy ions. When the fluid is maintained at a desired temperaturewithin the housing 232, the non-metal particles and the metal ions inthe fluid chemically bond to an external surface 253 of the cylindricalroller 251 to form a textured surface. The cylindrical roller 251 isrotated within the fluid to obtain a textured surface wherein between 7and 20 percent of slope angles on the textured surface have a valuebetween zero and five degrees.

The motor 242 is operably coupled to the cylindrical roller 251 and isprovided to rotate the cylindrical roller 251 at a predeterminedrotational speed. The motor 242 is disposed within the housing 232. Inan alternate embodiment, the motor 242 is disposed outside of thehousing 232 with a shaft (not shown) extending through the housing 232coupled to the cylindrical roller 251 for rotating the roller 251. Thecontrol computer 250 generates a signal (M8) that induces the motor 242to rotate the cylindrical roller 251 at a predetermined rotationalspeed.

The pump 244 is provided to pump the fluid containing the non-metalparticles and the metal ions from the housing 232 through thetemperature control unit 246 and the particle and metal-ionreplenishment unit 248. In particular, the control computer 250generates a signal (P1) that induces the pump 244 to pump the fluid fromhousing 232 through the unit 246 and the unit 248 and back to theinterior region 234.

The temperature control unit 246 is operably coupled to the pump 244 andreceives the fluid containing non-metal particles and the metal-ionsfrom the pump 244. The temperature control unit 246 is provided tocontrol a temperature of the fluid being pumped therethrough at adesired temperature that allows the co-deposition of the non-metalparticles and metal-ions onto the outer surface 253 of the cylindricalroller 251. The temperature control unit 246 monitors a temperature ofthe fluid in pump therethrough and either increases or decreases thetemperature of the fluid to the desired temperature.

The particle and metal ion replenishment unit 248 is operably coupled tothe temperature control unit 246 and receives the fluid containing thenon-metal particles in the metal-ions from the unit 246. The unit 248monitors the concentration of the non-metal particles and the metal ionsduring the co-deposition of the particles and metal ions on the surface253. It will be understood, that as the non-metal particles and themetal ions are bonded to the outer surface 253 of the roller 251, theconcentration of the non-metal particles and metal ions in the fluidwill be decreased. The unit 248 measures the concentration of thenon-metal particles and the metal ions in the fluid being pumpedtherethrough and adds an additional amount of non-metal particles andmetal ions to the fluid to maintain a desired concentration of eachmaterial. After the fluid is conditioned by the unit 248, the fluid isrouted to the interior region 234 of the housing 232.

Referring to FIG. 15, a cross-sectional view of a portion of a texturedsurface 253 of the cylindrical roller 251 is illustrated. The texturedsurface 253 was obtained utilizing the particle and metal ionco-deposition system 230. The textured surface 253 has a slope angledistribution wherein between 7 and 20 percent of slope angles on thetextured surface 253 have a value between zero and five degrees.

Referring to FIG. 16, a cross-sectional view of a portion of a texturedsurface 254 of the light collimating and diffusing film cut from atextured plastic layer formed by the cylindrical roller 251 isillustrated. The textured surface 254 has a slope angle distributionwherein between 7 and 20 percent of slope angles on the textured surface28 have a value between zero and five degrees.

Referring to FIG. 17, a system 270 for forming a textured surface on thecylindrical roller 278 in accordance with another exemplary embodimentis illustrated. The cylindrical roller 278 can be utilized either in themelt calendaring system 100 or the embossing system 150 to form atextured plastic layer used to obtain a film having physicalcharacteristics substantially similar to film 28 described above. Thesystem 270 includes a housing 272, a motor 280, a current source 282,and a control computer 284.

The housing 272 defines an interior region 274 for receiving acylindrical roller 278. The housing 272 holds an electrolyte fluidcontaining a plurality of metal ions 276. In one embodiment, theplurality of metal ions 276 comprise chromium ions. When a predeterminedcurrent density is applied in the electrolyte fluid, the metal ions 276bond to the outer surface 279 of the cylindrical roller 278 to form atextured surface. The cylindrical roller 278 is rotated within theelectrolyte fluid to obtain a textured surface wherein between 7 and 20percent of slope angles on the textured surface have a value betweenzero and five degrees.

The motor 280 is operably coupled to the cylindrical roller 278 and isprovided to rotate the cylindrical roller 278 at a predeterminedrotational speed for a predetermined time period. For example, the motor280 can rotate the cylindrical roller 278 at a rotational speed in arange of 1-10 revolutions per minute for a time period in a range of0.5-50 hours. The motor 280 is disposed within the housing 272. In analternate embodiment, the motor 280 is disposed outside of the housing272 with a shaft (not shown) extending through the housing 272 coupledto the cylindrical roller 278 for rotating the roller 278. Inparticular, the control computer 284 generates a signal (M9) thatinduces the motor 280 to rotate the cylindrical roller 278 at thedesired rotational speed.

The current source 282 is provided to apply a predetermined electricalcurrent density through the electrolyte fluid to induce metal ions inthe electrolyte fluid to adhere to the outer surface 279 of thecylindrical roller 278. The current source 280 is electrically coupledbetween a metal bar 275 immersed in the electrolyte fluid and thecylindrical roller 278. The current source 280 is further operablycoupled to the control computer 284. The control computer 284 generatesa control signal (I1) that induces the current source 282 to generate anelectrical current through the electrolyte fluid. In one embodiment, thecurrent source 280 generates a current density in a range of 0.001-0.1amperes per square millimeter in the electrolyte fluid to induce themetal ions in the fluid to adhere to the cylindrical roller 278.

Referring to FIG. 18, a system 300 for forming a textured surface on thecylindrical roller 318 in accordance with another exemplary embodimentis illustrated. The cylindrical roller 318 can be utilized either in themelt calendaring system 100 or the embossing system 150 to form atextured plastic layer that can be subsequently cut into a predeterminedshape to obtain a film having physical characteristics substantiallysimilar to film 28 described above. The system 300 includes engravingdevice 302, a linear actuator 312, a motor 314, and a control computer316.

The engraving device 302 is provided to iteratively contact the outersurface 319 of the cylindrical roller 318 at a predetermined frequencyto remove portions of the outer surface 319 to obtain a texturedsurface. In particular, the predetermined frequency is preferably withina range of 1000-1500 Khz. The engraving device 302 includes apiezo-electric transducer unit 304, a reciprocating member 306, acutting tool holder 308, and a cutting tool 310.

The piezo-electric transducer unit 304 is provided to iteratively movethe reciprocating member 306 upwardly and downwardly along the axis 307at the predetermined frequency in response to a control signal (P)received from the control computer 316. The reciprocating member 306 isfurther operably coupled to a first end of the cutting tool holder 308that holds a cutting tool 310.

Referring to FIGS. 19 and 20, the cutting tool 310 is provided to removeportions of the outer surface 319 of the cylindrical roller 318. Thecutting tool 310 is constructed from a diamond having a tip diameter(D1) in a range of 2-30 micrometers. The cutting tool 310 has a cuttingsurface 311 that extends 160 degrees about a center point of the tool310. The cutting surface 311 of the tool 310 iteratively contacts theouter surface 319 as the outer surface 319 is being rotated at apredetermined speed.

The linear actuator 312 is operably coupled to the engraving device 302for moving the engraving device 302 along an axis 303. The axis 303 issubstantially parallel to the outer surface 319 of the cylindricalroller 318. The linear actuator 312 moves the engraving device 302relative to the cylindrical roller 318 at a predetermined determinedaxial speed from a first end 321 to a second end 323 of the cylindricalroller 318. In an alternate embodiment, linear actuator 312 could becoupled to the cylindrical roller 318 to move the roller 318 in an axialdirection relative to a stationary engraving device.

The motor 314 is operably coupled to the cylindrical roller 318 torotate the roller 318 while the linear actuator 312 is moving theengraving device 302 along the axis 303 from the end 321 to the end 323.The control computer 316 generates a signal (M10) that induces the motor314 to rotate the cylindrical roller 318 at a predetermined rotationalspeed. In particular, the motor 310 rotates the cylindrical roller 318at a rotational speed within a range of 10-200 revolutions per minute.

Referring to FIG. 21, a system 330 for forming a textured surface on thecylindrical roller 340 in accordance with another exemplary embodimentis illustrated. The cylindrical roller 340 can be utilized either in themelt calendaring system 100 or the embossing system 150 to form atextured plastic layer that can be subsequently cut into a predeterminedshape to obtain a film having physical characteristics substantiallysimilar to film 28 described above. The system 330 includes a housing332, a motor 336, and a control computer 338.

Before explaining the operation of the system 330, a brief explanationof the structure of the cylindrical roller 340 will be provided.Referring to FIG. 22, the cylindrical roller 340 has a substantiallycylindrical inner portion 342 coated with a chemically resistant layer343. The chemically resistant layer 343 comprises a plastic layer. In analternate embodiment, the chemically resistant layer 343 comprises a waxlayer. In yet another alternate embodiment, the chemically resistantlayer 343 comprises a photo-resist layer. After the cylindrical roller340 has been coated by the chemically resistant layer 343, portions ofthe layer 343 at predetermined locations (e.g., locations 346) areremoved. Portions of the layer 343 are removed at predeterminedlocations using an energy beam, such as a laser. In an alternateembodiment, portions of the layer 343 are removed at the predeterminedlocations using a tool (not shown) having a hardness greater than thechemically resistant layer 343 but less than a hardness of thecylindrical inner portion 342. In yet another alternate embodiment, thechemically resistant layer 343 is removed at the predetermined locationsusing a lithographic process known to those skilled in the art.

The housing 332 defines an interior region 334 for receiving acylindrical roller 340. The housing 332 holds an etching solution forremoving exposed portions of the inner portion 342 of the cylindricalroller 340. The etching solution includes nitric acid wherein 5 to 25percent of a mass of the etching solution is nitric acid. In analternate embodiment, the etching solution includes hydrochloric acidwherein 5 to 25 percent of a mass of the etching solution ishydrochloric acid. When the cylindrical roller 340 is rotated within theetching fluid, the etching fluid removes portions of the cylindricalroller 340 proximate the locations 346 to form a textured surfacewherein between 7 and 20 percent of slope angles on the textured surfacehave a value between zero and five degrees.

The motor 336 is operably coupled to the cylindrical roller 340 and isprovided to rotate the cylindrical roller 340 at a predeterminedrotational speed. The motor 336 is disposed within the housing 332. Inan alternate embodiment, the motor 336 is disposed outside of thehousing 332 with a shaft (not shown) extending through the housing 332coupled to the cylindrical roller 340 for rotating the roller 340. Thecontrol computer 338 generates a signal (M11) that induces the motor 336to rotate the cylindrical roller 341 at a predetermined rotationalspeed. In particular, the motor 336 can rotate the cylindrical roller341 at a rotational speed in a range of 1-50 revolutions per minute.

Referring to FIG. 23, a system 370 for forming a textured surface on thecylindrical roller 390 in accordance with another exemplary embodimentis illustrated. The cylindrical roller 390 can be utilized either in themelt calendaring system 100 or the embossing system 150 to form atextured plastic layer that can be subsequently cut into a predeterminedshape to obtain a film having physical characteristics substantiallysimilar to film 28 described above. The system 370 includes an electrodeor an electrode array 372, a voltage source 374, a linear actuator 376,a motor 378, a pump 382, a filter 384, a dielectric fluid source 386,and a control computer 388.

The electrode 372 is provided to iteratively discharge an electric sparkthat contacts an outer surface 391 to remove portions of the surface 391to obtain a textured surface. The electrode 372 is operably coupled tothe voltage source 374 and receives a voltage from the voltage source374 to generate an electric spark having a voltage in a range of100-1000 volts. The voltage source 374 is operably coupled to thecontrol computer 388. The control computer 380 generates a signal (V2)that induces the voltage source 374 to apply a predetermined voltage tothe electrode 372. The electrode 372 is further operably coupled to thelinear actuator 376. When the cylindrical roller 390 is being rotated,the electrode 372 is moved along axis 373 and iteratively discharges anelectric spark to remove portions of the cylindrical roller 390 to forma textured surface wherein between 7 and 20 percent of slope angles onthe textured surface have a value between zero and five degrees.

The pump 382 is provided to pump a dielectric fluid from the dielectricfluid reservoir 386 through a filter 384 and finally through the nozzle380. The nozzle 380 directs the dielectric fluid onto the outer surface391 of the cylindrical roller 390. The dielectric fluid is utilized toconduct an electric spark therethrough to the outer surface 391 of thecylindrical roller 390. The nozzle 380 is further operably coupled tothe linear actuator 376.

The linear actuator 376 is operably coupled to both the electrode 372and the nozzle 380. The linear actuator 376 moves the electrode 372 andthe nozzle 380 along an axis 373 that is substantially parallel to theouter surface of the cylindrical roller 390. In particular, the linearactuator 376 moves the electrode 372 and the nozzle 380 along the axis373 from a first end 393 to a second end 395 of the cylindrical roller390.

The motor 378 is operably coupled to the cylindrical roller 390 torotate the roller 390 while the linear actuator 376 is moving both theelectrode 372 and the nozzle 380 along the axis 373 from the end 393 tothe end 395. The control computer 388 generates a signal (M12) thatinduces the motor 378 to rotate the cylindrical roller 390 at apredetermined rotational speed.

The light collimating and diffusing film and the method formanufacturing the film represents a substantial advantage over othersystems and methods. In particular, the system and method have atechnical effect of providing a plastic layer having a textured surfacecapable of diffusing light that can readily manufactured without havingany additional material being added to the plastic layer such aspolystryene beads or an acrylate solution.

While the invention is described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalence may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to the teachings of theinvention to adapt to a particular situation without departing from thescope thereof. Therefore, it is intended that the invention not belimited to the embodiments disclosed for carrying out this invention,but that the invention includes all embodiments falling with the scopeof the intended claims. Moreover, the use of the term's first, second,etc. does not denote any order of importance, but rather the term'sfirst, second, etc. are used to distinguish one element from another.

1. A tool for forming a textured surface on a light collimating anddiffusing film, comprising: a cylindrical portion being disposed about afirst axis and having an external textured surface and first and secondends, the cylindrical portion further having a first line disposedproximate the external textured surface extending substantially acrossthe cylindrical portion substantially perpendicular to the first end,the cylindrical portion further having a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end, the external textured surface having aplurality of projecting portions and a plurality of trough portions,wherein each projecting portion extends outwardly from at least oneadjacent trough portion, wherein the plurality of projecting portionsand the plurality of trough portions define a plurality of slope angles,wherein between 7 to 20 percent of the slope angles on the externaltextured surface proximate the first line or the second line have avalue between zero and five degrees.
 2. The tool of claim 1, whereinbetween 7 to 20 percent of the slope angles on the external texturedsurface proximate both the first line and the second line have a valuebetween zero and five degrees.
 3. The tool of claim 1, wherein between 7to 20 percent of the slope angles on the external textured surface havea value between zero and five degrees.
 4. A method for forming atextured surface on a cylindrical roller, the cylindrical roller beingdisposed about a first axis and having an external surface and first andsecond ends, the cylindrical roller further having a first line disposedproximate the external surface extending substantially across thecylindrical roller substantially perpendicular to the first end, thecylindrical roller further having a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end, comprising: rotating the cylindrical rollerat a predetermined rotational speed about the first axis; and emitting apulsating energy beam that contacts the external surface of thecylindrical roller at a predetermined intensity and moving the energybeam from the first end to the second end of the cylindrical rollerduring the rotation of the cylindrical roller, wherein the energy beamremoves portions of the outer surface to obtain the textured surface,the textured surface having a plurality of projecting portions and aplurality of trough portions, wherein each projecting portion extendsoutwardly from at least one adjacent trough portion, wherein theplurality of projecting portions and the plurality of trough portionsdefine a plurality of slope angles, wherein between 7 to 20 percent ofthe slope angles on the textured surface proximate the first line or thesecond line have a value between zero and five degrees.
 5. The method ofclaim 4, wherein between 7 to 20 percent of the slope angles on thetextured surface proximate both the first line and the second line havea value between zero and five degrees.
 6. The method of claim 4, whereinbetween 7 to 20 percent of the slope angles on the textured surface havea value between zero and five degrees.
 7. The method of claim 4, whereina linear speed of an external surface of the cylindrical roller iswithin a range of 25-2500 millimeters per second.
 8. The method of claim4, wherein the energy beam is moved relative to the cylindrical rollerat a speed within a range of 0.001-0.1 millimeters per second.
 9. Themethod of claim 4, wherein the energy beam has a focal diameter at theexternal surface of the cylindrical roller in a range of 0.005-0.05millimeters.
 10. The method of claim 9, wherein the energy beamcontacting the cylindrical roller has an energy level in a range of0.05-1.0 Joules delivered over a time period in a range of 0.1-100microseconds for a predetermined area of the cylindrical roller.
 11. Themethod of claim 4, wherein the energy beam comprises a laser beam. 12.The method of claim 11, wherein the laser beam has a wavelength of 1.06microns.
 13. The method of claim 11, wherein the laser beam comprises aNd:YAG laser beam.
 14. The method of claim 4, wherein the energy beamcomprises an electron beam.
 15. The method of claim 4, wherein the beamcomprises an ion beam.
 16. The method of claim 4, wherein the texturedsurface comprises a plurality of projecting portions and a plurality oftrough portions, wherein each projecting portion extends outwardly fromat least one adjacent trough portion.
 17. The method of claim 16,wherein an average height of the plurality of projecting portions iswithin a range of 25-100 percent of an average width of the plurality ofprojecting portions.
 18. The method of claim 16, wherein an averagewidth of the plurality of projecting portions is within a range of0.5-100 microns.
 19. A method for forming a textured surface on acylindrical roller, the cylindrical roller being disposed about a firstaxis and having an external surface and first and second ends, thecylindrical roller further having a first line disposed proximate theexternal surface, the first line extending substantially across thecylindrical roller substantially perpendicular to the first end, thecylindrical roller further having a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end, comprising: rotating the cylindrical rollerat a predetermined rotational speed about the first axis in anelectrolyte fluid, the cylindrical roller being electrically grounded;and applying a predetermined cuffent density to the electrolyte fluidwherein metal ions in the fluid bond to the external surface of thecylindrical roller to form the textured surface, the textured surfacehaving a plurality of projecting portions and a plurality of troughportions, wherein each projecting portion extends outwardly from atleast one adjacent trough portion, wherein the plurality of projectingportions and the plurality of trough portions define a plurality ofslope angles, wherein between 7 to 20 percent of the slope angles on thetextured surface proximate the first line or the second line have avalue between zero and five degrees.
 20. The method of claim 19, whereinbetween 7 to 20 percent of the slope angles on the textured surfaceproximate both the first line and the second line have a value betweenzero and five degrees.
 21. The method of claim 19, wherein between 7 to20 percent of the slope angles on the textured surface have a valuebetween zero and five degrees.
 22. The method of claim 19, wherein thecylindrical roller rotates in the electrolyte fluid at a rotationalspeed in a range of 1-10 revolutions per minute for a time period in arange of 0.5-50 hours.
 23. The method of claim 19, wherein the metalions comprises chromium ions.
 24. The method of claim 19, wherein thepredetermined current density is in a range of 0.001-0.01 amperes persquare millimeter.
 25. The method of claim 19, wherein the texturedsurface comprises a plurality of projecting portions and a plurality oftrough portions, wherein each projecting portion extends outwardly fromat least one adjacent trough portion.
 26. The method of claim 25,wherein an average height of the plurality of projecting portions iswithin a range of 25-100 percent of an average width of the plurality ofprojecting portions.
 27. The method of claim 25, wherein an averagewidth of the plurality of projecting portions is within a range of0.5-100 microns.
 28. A method for forming a textured surface on acylindrical roller, the cylindrical roller being disposed about a firstaxis and having an external surface and first and second ends, thecylindrical roller further having a first line disposed proximate theexternal surface, the first line extending substantially across thecylindrical roller substantially perpendicular to the first end, thecylindrical roller further having a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end, comprising: rotating the cylindrical rollerat a predetermined rotational speed about the first axis in a fluidcontaining metal ions and non-metal particles; and chemically bondingthe metal ions and the non-metal particles to the external surface ofthe cylindrical roller to form the textured surface, the texturedsurface having a plurality of projecting portions and a plurality oftrough portions, wherein each projecting portion extends outwardly fromat least one adjacent trough portion, wherein the plurality ofprojecting portions and the plurality of trough portions define aplurality of slope angles, wherein between 7 to 20 percent of the slopeangles on the textured surface proximate the first line or the secondline have a value between zero and five degrees.
 29. The method of claim28, wherein between 7 to 20 percent of the slope angles on the texturedsurface proximate both the first line and the second line have a valuebetween zero and five degrees.
 30. The method of claim 28, whereinbetween 7 to 20 percent of the slope angles on the textured surface havea value between zero and five degrees.
 31. The method of claim 28,wherein the non-metal particles comprise silica particles having a sizein a range of 1-100 micrometers.
 32. The method of claim 31, wherein thesilica particles comprise solid silica particles.
 33. The method ofclaim 31, wherein the silica particles comprise hollow silica particles.34. The method of claim 31, wherein the silica particles comprise poroussilica particles.
 35. The method of claim 28, wherein the non-metalparticles comprise alumina particles having a size in a range of 1-100micrometers.
 36. The method of claim 35, wherein the alumina particlescomprise solid alumina particles.
 37. The method of claim 35, whereinthe alumina particles comprise porous alumina particles.
 38. The methodof claim 28, wherein the metal ions comprise one of nickel ions andnickel alloy ions.
 39. The method of claim 28, wherein the texturedsurface comprises a plurality of projecting portions and a plurality oftrough portions, wherein each projecting portion extends outwardly fromat least one adjacent trough portion.
 40. The method of claim 39,wherein an average height of the plurality of projecting portions iswithin a range of 25-100 percent of an average width of the plurality ofprojecting portions.
 41. The method of claim 39, wherein an averagewidth of the plurality of projecting portions is within a range of0.5-100 microns.
 42. The method of claim 28, wherein the non-metalparticles comprise diamond particles having a size in a range of 1-100micrometers.
 43. A method for forming a textured surface on acylindrical roller, the cylindrical roller being disposed about a firstaxis and having an external surface and first and second ends, thecylindrical roller further having a first line disposed proximate theexternal surface, the first line extending substantially across thecylindrical roller substantially perpendicular to the first end, thecylindrical roller further having a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end, comprising: rotating the cylindrical rollerat a predetermined rotational speed about the first axis; applying adielectric fluid on the cylindrical roller; and interatively dischargingan electric spark from one or more electrodes disposed proximate thecylindrical roller, the electric spark contacting the external surfaceof the cylindrical roller that heats and melts a predetermined amount ofmetal on the cylindrical roller to form the textured surface, theelectric spark being moved from the first end to the second end of thecylindrical roller during the rotation of the cylindrical roller, thetextured surface having a plurality of projecting portions and aplurality of trough portions, wherein each projecting portion extendsoutwardly from at least one adjacent trough portion, wherein theplurality of projecting portions and the plurality of trough portionsdefine a plurality of slope angles, wherein between 7 to 20 percent ofthe slope angles on the textured surface proximate the first line or thesecond line have a value between zero and five degrees.
 44. The methodof claim 43, wherein between 7 to 20 percent of the slope angles on thetextured surface proximate both the first line and the second line havea value between zero and five degrees.
 45. The method of claim 43,wherein between 7 to 20 percent of the slope angles on the texturedsurface have a value between zero and five degrees.
 46. The method ofclaim 43, wherein the electric spark has a voltage of 100-1000 volts.47. The method of claim 43, wherein the textured surface comprises aplurality of projecting portions and a plurality of trough portions,wherein each projecting portion extends outwardly from at least oneadjacent trough portion.
 48. The method of claim 47, wherein an averageheight of the plurality of projecting portions is within a range of25-100 percent of an average width of the plurality of projectingportions.
 49. The method of claim 47, wherein an average width of theplurality of projecting portions is within a range of 0.5-100 microns.50. A method for forming a textured surface on a cylindrical roller, thecylindrical roller being disposed about a first axis and having anexternal surface and first and second ends, the cylindrical rollerfurther having a first line disposed proximate the external surface, thefirst line extending substantially across the cylindrical rollersubstantially perpendicular to the first end, the cylindrical rollerfurther having a second line extending around a periphery of thecylindrical portion substantially a predetermined distance from thefirst end, comprising: rotating the cylindrical roller at apredetermined rotational speed about the first axis; and iterativelycontacting the external surface of the cylindrical roller using acutting tool at a predetermined frequency, the cutting tool moving fromthe first end to the second end of the cylindrical roller during therotation of the cylindrical roller, wherein the cutting tool removesportions of the external surface to obtain the textured surface, thetextured surface having a plurality of projecting portions and aplurality of trough portions, wherein each projecting portion extendsoutwardly from at least one adjacent trough portion, wherein theplurality of projecting portions and the plurality of trough portionsdefine a plurality of slope angles, wherein between 7 to 20 percent ofthe slope angles on the textured surface proximate the first line or thesecond line have a value between zero and five degrees.
 51. The methodof claim 50, wherein between 7 to 20 percent of the slope angles on thetextured surface proximate both the first line and the second line havea value between zero and five degrees.
 52. The method of claim 50,wherein between 7 to 20 percent of the slope angles on the texturedsurface have a value between zero and five degrees.
 53. The method ofclaim 50, wherein the predetermined rotational speed of the cylindricalroller is within a range of 10-200 revolutions per minute.
 54. Themethod of claim 50, wherein the predetermined frequency is within arange of 1000-1500 kilohertz.
 55. The method of claim 50, wherein thetextured surface comprises a plurality of projecting portions and aplurality of trough portions, wherein each projecting portion extendsoutwardly from at least one adjacent trough portion.
 56. The method ofclaim 55, wherein an average height of the plurality of projectingportions is within a range of 25-100 percent of an average width of theplurality of projecting portions.
 57. The method of claim 55, wherein anaverage width of the plurality of projecting portions is within a rangeof 0.5-100 microns.
 58. A method for forming a textured surface on acylindrical roller, the cylindrical roller being disposed about a firstaxis and having an external surface and first and second ends, thecylindrical roller further having a first line disposed proximate theexternal surface, the first line extending substantially across thecylindrical roller substantially perpendicular to the first end, thecylindrical roller further having a second line extending around aperiphery of the cylindrical portion substantially a predetermineddistance from the first end, comprising: coating the cylindrical rollerwith a chemically resistant layer, wherein the chemically resistantlayer is removed at predetermined locations to expose the underlyingcylindrical roller surface at the predetermined locations; and rotatingthe cylindrical roller at a predetermined rotational speed about thefirst axis in a container containing an etching solution, wherein theetching solution removes portions of the cylindrical roller at thepredetermined locations to obtain the textured surface, the texturedsurface having a plurality of projecting portions and a plurality oftrough portions, wherein each projecting portion extends outwardly fromat least one adjacent trough portion, wherein the plurality ofprojecting portions and the plurality of trough portions define aplurality of slope angles, wherein between 7 to 20 percent of the slopeangles on the textured surface approximate the first line or the secondline have a value between zero and five degrees.
 59. The method of claim58, wherein between 7 to 20 percent of the slope angles on the texturedsurface proximate both the first line and the second line have a valuebetween zero and five degrees.
 60. The method of claim 58, whereinbetween 7 to 20 percent of the slope angles on the textured surface havea value between zero and five degrees.
 61. The method of claim 58,wherein the cylindrical roller is rotated at a rotational speed in arange of 1-50 revolutions per minute.
 62. The method of claim 58,wherein 5 to 25 percent of a mass of the etching solution is nitricacid.
 63. The method of claim 58, wherein 5 to 25 percent of a mass ofthe etching solution is a hydrochloric acid.
 64. The method of claim 58,wherein the chemically resistant layer is removed at the predeterminedlocations using a lithographic process.
 65. The method of claim 58,wherein the chemically resistant layer is removed at the predeterminedlocations using an energy beam.
 66. The method of claim 58, wherein thechemically resistant layer is removed at the predetermined locations bycontacting the cylindrical roller with a tool, the tool having ahardness greater than the chemically resistant layer but less than ahardness of the cylindrical roller.
 67. The method of claim 58, whereinthe chemically resistant layer comprises a photo-resist layer.
 68. Themethod of claim 58, wherein the chemically resistant layer comprises awax layer.
 69. The method of claim 58, wherein the chemically resistantlayer comprises a plastic layer.
 70. The method of claim 58, wherein thetextured surface comprises a plurality of projecting portions and aplurality of trough portions, wherein each projecting portion extendsoutwardly from at least one adjacent trough portion.
 71. The method ofclaim 70, wherein an average height of the plurality of projectingportions is within a range of 25-100 percent of an average width of theplurality of projecting portions.
 72. The method of claim 70, wherein anaverage width of the plurality of projecting portions is within a rangeof 0.5-100 microns.